The present invention generally relates to data storage and more specifically to methods and apparatus for providing trusted time stamping in a storage system.
With the increase in the amount of digital data being created and/or modified and moreover used in official and public affairs, it has become more desirable to prove the time that the digital data was created and/or modified. In one example, an internal timer in a computer system may be used to show the time and date that the digital data was created and/or modified. However, the internal timer may be easily changed to reflect a false date or time. Accordingly, the internal timer in the computer system does not provide a trusted date or time to the public.
A time stamp may be provided by a public authority and attached to the data in the computer system. This time stamp is used to prove that the data is as it was at the time when the time stamp was attached to the data. Examples of commercial services that provide time stamps include services provided by Surety, DigiStamp, I.T. Consulancy, Seiko Instruments, Amano, and like. Also, time stamping is standardized as “Simple Protocol (RFC 3161)” by IETF.
More and more data is being preserved for a long period of time in storage systems, such as in Redundant Arrays of Inexpensive Disks (RAID). For example, the U.S. Securities and Exchange Commission (SEC) regulates the exchanges between members, brokers, and dealers to preserve records of all communications with their customers as well as all financial transaction records in a non-erasable format (write once read many (WORM) format) for a certain amount of years under the Securities Exchange Act of 1934, Rule 17 A-4. Also, the National Association of Securities Dealers, Inc. (NASD) has similar regulations found at Rules 3010 and 3110. These regulations require WORM capability in a storage system in that data cannot be erasable or modifiable for a certain periods of time. The data being stored during these time periods also needs to be trusted.
Currently, storage systems use an internal timer to indicate a time data was stored. This suffers from the same problems as discussed above in that the internal timer may be changed to provide a time stamp that is false.